The present invention relates to a method and apparatus for the stepwise static testing of the respective connections and integrated subsystems of a microprocessor-based system.
Devices for testing microprocessors have been referenced, for example in "Computer Design", March 1979, page 160 and further, "Troubleshooting Microprocessors With a Logic Analyzer System", and "L'electronique Industrielle", No. 25, dated 1.12.81, page 41 and further, "L'analyse de signature pour la maintenance sur le site". Repair devices are being manufactured by FLUKE, 606 Rue Fourny, ZI Centre, BP.31, 78530 BUC, France. However these publications and devices are intended for the development and testing of microprocessors and their peripheral integrated circuits, but not their connections; furthermore, these various devices are intended for use by experts for providing specific maintenance for high-level professional products; such products to be used by electronic data processing experts are expensive and comparatively complicated to operate. On the other hand, distributors and repair technicians for microprocessor-based systems that are in fact mass products, such as small domestic appliances and video-games often are not skilled in the art of data processing but are used to the problems occurring in reparing products like conventional television sets for which voltmeters and analog oscilloscopes are suitable tools. However, the latter are quite inadequate for use with digital systems. The difficulty in testing connections are circuits with these well known tools for the origin of a fault stems from the fact that characterizing signals during operation of a digital system are transitory and non-recurrent; on the other hand, the circuits are very vulnerable for overvoltages which could be produced during conventional electronic tests, which would thus itself cause (further) breakdowns.
Adequate testing would require digital means, such as a storage oscilloscope, but this would represent and overly large investment for repairing small and/or inexpensive mass-products. Furthermore, the operation of such means would be complicated and often advance knowledge of the operation of system would be required.
It is an object of the invention to provide an inexpensive, simple to operate, and static method and apparatus for the static testing of respective connections and integrated subsystems of a microprocessor-based system for use by the general public.